1. Field of the Invention
The present invention is related to image processing, and more particularly to a phase detection apparatus capable of detecting the phase utilized in an image encoding/decoding process.
2. Description of the Prior Art
Regarding to conventional image processing, a predetermined encoding method is utilized without dynamically adjusting the image data in the encoding process. For example, referring to FIG. 1, FIG. 1 is a functional block illustrating a prior art DVD player 100. The data is mostly stored in a MPEG format in the DVD disc 105. After the MPEG data stored in the DVD disc 105 is read by the read/write head of the DVD player 100, the MPEG data is encoded by a video encoder 110 to generate a composite signal. Then, the composite signal will be decoded by a video decoder 120, and a brightness signal and a color signal are thus obtained, such as a YUV signal.
In the prior art, the composite signal encoded by the video encoder 110 can be represented by the equation Y+(U sin(ωt)+V cos(ωt)), wherein Y represents the brightness of the composite signal, as U and V represents the color of the composite signal, and wt represents the phase utilized when proceed the image encoding. The image encoder 110 adopts a predetermined phase to encode the MPEG data; and incorporates the predetermined phase into the color burst signal of the composite signal. Therefore, the image decoder 120 can obtain the predetermined phase from the color burst signal and decode the composite signal to obtain the brightness and the color. Accordingly, the YUV signal can be obtained from the composite signal and displayed.
However, for the image data with cross color phenomenon, the predetermined phase to encode/decode the image data may result in errors. In other words, the predetermined phase may not be appropriate for all the image data, and consequently will decrease the quality of the decoded image. In other words, the image quality is limited to the phase used in the front-end encoder/decoder without dynamic compensation.